Artificial material and process for making same



Patented Oct. 11, 1932 T PATENT orFicE LEON LiLInNrELn, or VIENNA,AUSTRIA- ARTIFICIAL MATERIAL AND iROCESS FOR MAKING SAIaIE No Drawing.Original application filed-J'urieB, 1926, Serial No. 113,582, and inAustria January 5, 1926.

Divided and this application'filed September 19, 1929. Serial No.393,829.

' Heretofore strong mineral acids (i. e. acids which exercise aplasticizing effect, such as H SO of 45% or 50% or stronger or .HCl of25% or stronger) have not been used as 5 coagulating or spinning bathsin the manufacture of artificial materials, such as artificial threadsand films from viscose, because, by means of such acids, the formationof a lustrous thread, band, film or the like has been consideredimpossible. (See U. S. Patent 836,452.) I

Now I have discovered that this holds good with a strong halogenhydracid, such ,as'hydrochloric acid containing up to about 25 per cent.of H01, but that hydrochloric acid containing about to 40 per cent. ofH01, and preferably hydrochloric'acid containing more than 25 per cent,for example per cent. of HCl, when used as coagulating or spinning bathfor'viscose brought into the form of a thread or film or band or thelike, yieldsthreads, film, bands'or the like which have a good lustre. 1But-what is still more important: I have I 213 discovered that threads,films, bands'or the like manufactured from viscose by means ofhydrochloric acid containing at least about '25 per cent. of HCl,preferably however more v than 25 per cent, of HCl, for example 35 soper cent. of HCl, with regard to their tensile strength, surpass anyartificial thread known hitherto and in some cases approach, in somecases equal,and in some cases even surpass v even natural fibres, suchas cotton or Wool 35 or real silk. For example, it offers no difficultyto produce according to the present process, artificial silk or staplefibre that has a dry tenacity of more than 2 grammes and even. more than3 grammes per denier, for ex- 4 ample?) or even 3, 5 to 4 grammes perdenier and in some cases even more than 4 grammes per denier, and a wettenacity of 1,5 to 2,5 grammes per denier and more.

A further advantage of the artificial threads manufactured according tothe present process over ordinaryviscose silk is their higher resistanceto aqueous alkalles and to soa I have. further found thatit isadvantageous to the tensile strength of the artificialmaterials,particularlythreads,manufactured according to the presentprocess, to stretch the threads either in the coagulating bath orbetween the coagulating bath and the collecting' device or in bothplaces.

I The process is carried out in such a manner that viscose is broughtinto the form of an artificial material and coagulated by means ofhydrochloric acid, containing at least 25 per cent. of HCl, for examplehydrochloric acid containing 35 per cent. of by drogen chloride. In mostcases, for instance in manufacturing artificial threads orfilaments, orfilms, or hands, or plates, this can be effected in such a manner thatthe viscose is caused to pass through suitably formed openings intohydrochloric acid, containing 25 to per cent. of HCl, for instancehydrochloric acid of 35 per cent. strength. The strong hydrochloricacid'may be employed by itself or in admixture with one or more suitableinorganic substances, for example with another strong mineral acid suchas phosphoric acid, or with a neutral or acid salt,

such as sodium sulphate, sodium bisulphate, ammonium sulphate, magnesiumsulphate, zinc sulphate, sodium bisulphite, sodium sulphite, sodiumnitrite, boric acid or the like. To the strong hydrochloric acid or itsmixture with another strong acid or with one or more of the inorganicsubstances mentioned above, there may be added one or more organicbodies, such as glycerol or a sugar, for example glucose, or alcohol ora salt of an organic base, for'exampleof aniline, or an organic acid,such as acetic acid or formic acid or lactic acid or oxalic acid. If asalt is added which is capable of reacting with the strong hydrochloricacid, the strength of the acid should be so chosen that, after theamount required for the reaction is used up, the coagulating bathcontains .freerhydrochloric acid of the desired strength, but at anyrate not less than 25 parts by weight of hydrogen chloride in 100parts'by weight of the precipitating bath.

The suitable strength of the acid depends. ceteris paribus, partly onthetime ofmatur ing given the alkali cellulose, partly on the timeofripening given the finished viscose and partly on the viscosity oramount of cellulose contained in the viscose. As a rule, to whichhowever the invention is not confined, it may be stated that withviscoses which have matured for several days and/or viscoses that havebeen prepared from alkali 7 cellulose that has been allowed to maturefor a longer time, for example 2 to 3 days and/or viscoses that are poorin cellulose or little viscous respectively, preferably an acid is usedwhich is not so strong as would be used when treating viscoses that havenot been allowed to mature or have been allowed to mature for a shorttime (for instance 3 to 48 hours) only and/or have been prepared fromalkali cellulose that has been not allowed to .mature at all orhas beenallowed to mature for ashorter time than usual, for

.examplefor'3 to 48 hours, and/or are rich in cellulose or viscousrespectively. The strength of theacid is further, to a certain degree,dependent on the length of immersi'on in the coagulating bath-and thetension given the coagulated material in theacid or outside it, torexample between the coagulat .ing bath and the collecting device, for example bobbin. V The precipitating bath may be kept at room temperatureor at a temperature exceeding room. temperature, for example at25,1;0'50" 0., or at a temperature lower than room temperature, forexample at O to 5 C.,

.or'even below 0 (3., for example at from 1'to-10 G.

.The length of immersion of the thread or filament or plate or film orband in the strong acid or in the bath containing it may be variedwithin wide limits, for examples from a'cid,.be heated or steamed beforeor after.

drying. r r

a Any viscose prepared according to any process or any method knownhitherto may be used in the present process. The process gives excellentresults with viscoses that are prepared from alkali cellulose that hasbeen allowed to mature for such a time as it is commonly given thealkali cellulose in the artificial silk or film art and also withviscoses-in the manufacture of which alkali celluloseis employed whichhas'inot been-allowed to mature at'all or has been allowed to. maturefora shorter time than such as. is

usual in the artificial silk or film art, i. e. not longer than about 48hours, for example 1 to 24 hours. I I

The present process gives excellent results with such viscoses also asare prepared without making alkali cellulose, i. e. by direct mixing theingredients.

If desired, there may be added to the viscose one or more suitablesubstances known in the viscose-silk art, for example glycerol orglucose orsodium sulphate or sodium sulphlte or sodium blsulplnte orammonium sulphate or an alkali silicate or an alkali aluminate or ammona. i i

The process being open to manifold variations, it isnotintended toconfine the invention tot-he following examples given for the practicalcarrying outof the process.

. (a)."10O,parts'by weight of sulphite-pulp are impregnated with 900 to.2000 parts by weight of. a caustic soda solution of 18 per cent.strength at 15 to "18 (1., and themixture allowed to stand for ;3 to V2%hours. Then the mass is pressed to 300 to 400 parts by weight, and theresidue comminuted by hand or, in a: suitable apparatus, for instance ina cooled shredder. The comminuted soda cellulose is then kept for tof72hours at room temperature, whereafter 30 to '60 parts by weight ofcarbon bisulphideare added, and the reacting mixture,,preferably understirring (for example in a closed kneading machine) or agitating (forexample in a sulphidizing drum), kept for several (for example lto 8)hours: at 16 to 20 C. Thereafter the excess of the carbon 'b'isulphideis removed by driving oil or evacuating, and

' then'the sulphidized mass is dissolvedin water or dilute causticsodasolution in such a manner that the viscose contains about .8 to 12per cent. of celluloseldetermined in the known manner by precipitatingwith acid, washing. and drying), If caustic soda solution is used, itmaybe for example so chosen that, if the amount of caustic soda thatwaspresent in the soda celluloseis taken into consideration the finalviscose contains 5 to S per cent. caustic soda. The viscose solutionthus obtainedis then filtered in a known manner through cotton wool or adensecott on fabric or through both and freed'from. gas bubbles if any.Immediately after, or after it has been allowed to ripen at 16-18 C. fora shorter (for example 12 hours to'two days) or a longer (forexamplefour days or seven days) time, the viscose is spun in a known mannerinto oneofthe following precipitating baths:

(1). Hydrochloric acid of 25 to 40 per cent. strength, or" 7 (2)Hydrochloric acid strength, or I V V 1' j (3) A solutioncontaining,9.345;to 9.48 per of 35 per cent 1 by weight of ammoniumsulphate and '25 to 40 per cent hydrogenchloride.

. p (4) A solution containing to 7.5 per cent.

by weight of glucose and 25 to 40 per cent.

hydrogen chloride.

The temperature of the coagulating bath is kept at 0 to 16" (1., forinstancel at 8 0.,

The length of immersion in the coagulatbath of the threads formingtherein may be short, for example centimetres, or more long, forinstance from'80 to 100 centimetres and more. They are then collected ina known manner on a bobbin or in a spinning centrifuge which may beplaced either by the precipitating bath or at a distance from to 120centimetres from the bath,

V whereupon the threads are washed and dried.

The threads may be stretched in any known manner whilst they are in thecoagulating bath, or after they have been removed from the bath, i. e.between the coagulating bath and the collecting device. This may be donefor example either by choosing a more or less long distance between thebath and the collecting device, or by leading the threads over rods orhooks arranged between the nozit of speed possible is dependent partlyupon the temperature of the coagulating bath, partly upon the length ofimmersion, partly upon the distance between the coagulating bath and thecollecting device, partly upon the degree of stretching given the threadduring spinning, and partly upon the quantity of viscose delivered bythe pump. The following examples to which, however, the process is notintended to be limited, may be adduced for the purpose of illustration.

(1) If the coagulating bath is used at a temperature below 0 (3., forexample at minus 5 (1, and if the length of immersion is 60 to 120, forexample 80 centimetres, and if the distance between the coagulating bathand the collecting device, for example bobbin, is 60 to 150 centimetres,for instance 120 centimetres, and if the stretching given the threadbetween the coagulating bath and the collecting device is comparativelyhigh, and if the pump delivers about 2 to 3 cubic centimetres of viscosea minute, then the speed of 18 to 26 meters a minute, at the outside ofmeters a minute is recommendable.

(2) If all spinning conditions, remain the same as in (1), except thatthe pump delivers-4to 5 cubic centimetres of viscose a minute, then aspeed of to 60 meters a minute may be employed.

(3) If the spinning conditions are exact- 1y as in (1) except that thetemperature of the coagulating bath is plus 4 to plus 25 C.,'for example8 0., the speed may be to meters a minute.

If in (1) the length of immersion hr the distance between thecoagulating bath and the collecting device or both are shortened, thespeed may be increased.

Before being washed, the threads may be treated in any known manner witha bath known in the viscose-silk art, for example a solution of sodiumbisulphate or sodium bisnilphite or with dilute sulphuric acid or the lie. i

The Washed threads may, before or after drying, be heated (for exampleat IOU-110 C.) or steamed.

They may also be treated with any desulphurating or bleaching agentknown in the viscose art. 1

(b). The mode of operation is as in (a), except that 75 to 150 parts byweight of car- 'bon bisulphide are employed for the sulphidizing of thesoda-cellulose.

(a). The mode of operation is as in (a) or (b), with the diiference thatthe sodacellulose is pressed to 200 parts by Weight.

[I (a) to (0) strength.

(2) Hydrochloric acid strength.

(3) A solution containing 9.34 to 9.48 per cent. ammonium sulphate and25 to 4.0 per cent of hydrogen chloride.

1) A solution containing 5 to 7.5 per cent. by weight of glucose and 25to 40 per cent. hydrogen chloride.

Mode of operation as in Example I (a) or I (b) or I (0) oras in ExampleII (a) or II (b) or II (0) with the exception that the viscose is notallowed to mature at all or to mature for 12 to 48 hours only, and thatas coagulating bath hydrochloric acid of 25 to 40 per cent. strength,for instance hydrochloric acid of 35 per cent. strength at 6 to 10 C. isused. In using so strong an acid it is preferable to run the spinning ata high speed, for exof 35 per cent.

ample 40 to 60 meters a minute.

IV (a) to (e) (a). 100 parts by weight of sulphite pulp residuecomminuted byhandor in a suitable apparatus, for instance in a cooledshredden,

Immediately or soon (for. example 1 hour) after the comminutionhas takenplace, 30 to 60 parts by weight of carbon bisulphide are adde d,and thereacting mixture, preferably under stirring (for example in a closedknead- 7 ing machine) or agitating (forexample in a sulphidizing drum)kept for several (for example 4 to 12 hours at 16 to 20 0. Thereaftertheexcess of the carbon bisulphide'is weight of a caustic soda; solutionof-6,5 to 10 removed by driving off or evacuating, and the sulphidizedmass, the weight of which generally amounts to from about330 to 400parts by weight, is dissolved in 650 to 900 parts. by

per cent. strength. The viscose solution thus obtained is then filteredin a known manner through cotton wool or a dense cotton fabric orthrough both and freed from gas bubbles if any. Immediately after, orafter it has been allowed to ripen'at1618 C. for a shorter (for example12 hours to two days) or a longer (for example four days or seven days)time, the viscose is spun in a knownmanner into one of the followingprecipitatingbaths (1) Hydrochloric acid of'25 to 40 per cent. strength,or V (2) Hydrochloric acid of 35 per cent. stren'gtlnorj 1 7 (3) Asolution containing 9.34 to 9.48 per cent. byweightof ammonium sulphateand to 40 per cent. hydrogen chloride.

A solution containing 5 to 7.5 per cent. by Weight of glucose and 25 to40 per cent.

hydrogen chloride.,

The temperature of the coagulating bath is kept at 0 to16 C.,forinstance at 8 C., or at 4 130 8 C.

The spinning and treating of the'threads' v during and after spinning isdone in the same manner as described in the foregoing eXamles.

(5).,The mode of operationis as in (a), with the difierence that acaustic soda solution of 3 to 5 per cent. strength is employed 1 for thedissolvingof the sulphidized sodacellulose. Accordingly, the viscose issomewhat more viscous.

(5), except that 75 to 150 parts by weight of carbon bisulphide are.employed for the sulphidizing of the soda-cellulose.

(cl). The mode of operation is as in (a) or (b) or (c), with thedifference that the sodacellulose is pressed to 200 partsby weight.

(e). The mode of operation is as in (a) or (b) or (0) or (d), with thedifference that hydrochloric acidof 25 to 40 per cent. strength (0). Themode-of operation is as. in (a) or at 8 used ajs coagulating bath, theviscose being 12 to 48hours old and the. speed of spinning about tometers a minute.

. V? to The method of preparing the viscos'e'differs from that describedin IV (a) ,or (b) or ('0) or (d) or (e) in that the soda-cellulose,after pressing and comminuting and before being sulphidized, is allowedto ripen for 3 to 24 hours at 16 to 20 C. V The amount and concentrationof the caustic soda solution used for the dissolving of thesulphidizedma'ss. may be equal to those used in Example IV or somewhatlower, for example so as to produce a 1 0 tov 12 per cent.

viscose" (calculated on starting cellulose).

' The working up into threads. is; edectedas in IV (a) tote). v I

" V! (a) to. (d)

(a). 80400 parts by weight or finelydi- 'vided sulphiteepulp or bleachedcotton .or

.mixed with 920900 parts by weight of a' causticsoda solution of 8 to 10per cent. strength. To this mixture. 40 to 150 parts by weight of carbonbi'sulphide are added and the reacting mixture kept at room tem-'viscose is spun in a known manner into one of the following coagulatingbaths:

' (1) Hydrochloric acidof 25 to 40 per cent, strength, or

(2) Hydrochloric acid of 3w5 per cent.

strength, or p v v (3) A solution containing 9.34 to 9.48 per cent. byweight of'ammonium sulphate and 25 to 40 per cent. hydrogen chloride.

(4) Asolution containing5 to 7.5 per cent. by weight-of glucose and 25to 40 per cent. hydrogen chloride. 1 V

lhetemperature of the coagulating bathis kept at 0 to 16 (3.,for'instance at8. C. or at --4to8 The spinning and treating of thethreads is done as in the foregoing examples.

(6). ,Mode of operation as in ,(a) with the exception that the viscoseis prepared according to, the method 3 described in the British Patent212,865, for example accord ing to the following examples of saidspecification; I (a) to (e) or' II (a) to "(0) or III(a) to (0) or IV(a) to (e) or V (a) to (b) or VI (a) to (0) or VII or VIII or-IX or X orXII or XIII.

. (0'). Mode of operation asin (a) or (b),

with the exception that, before or after the addition of carbonbisulphide takes place, a small quantity of a catalyzer is added to themixture of the cellulosic body with the caustic alkali solution,forexample 0,2 to 1 parts by weight of a soluble chromic salt or nickelsalt or iron salt.

(d). Mode of operation as in (a) or (b),

. with the difierence that, before or after the addition of carbonbisulphide takes place, a small quantity of a soluble peroxide, such as5 to parts by weight of sodium peroxide to 100 parts by weight ofstarting cellulose are added.

' VII J the weight of the sulphidized mass being 330 parts. The finalviscose contains 8 per cent. of starting cellulose.

The filtering and spinning of this viscose and the treatment of thethreads is done as in the previous examples.

Examples for producing staple fibre follow automatically from the foregong examples.

According to the foregoing examples, it is possible to obtain artificialsilk or staple fibre which has a considerably higher dry and wettenacity than silk spun under same spinning conditions, but by means ofchemicals customary in the viscose silk-art, for example by using aknown precipitating bath. For example: It is not difiicult to produceafter the present process artificial silk having a dry tenacity of morethan 2 grammes per denier, even more than 3 grammes per denier, forexample 3 grammes to a grammes per denier and a wet tenacity of 1,5 to2,5 grammes per denier and more.

VIII

A viscose prepared as described in Example I or II or III or IV or VI orVII is caused to pass through a suitable hopper or slit in one of thecoagulating liquors mentioned in these examples,and after having leftthe precipitating bath, is washed and dried in any known manner.

A cotton fabric is impregnated or filled or coated once or several timeswith a viscose prepared according to one of the methods described inExample I or II or III or IV or V or VI or VII or VIII, for whichpurpose any suitable machine, such as a padding machine or a backfilling machine or a spreading machine may be employed. To the viscosethere may be added a filling substance, for instance talcum or chinaclay or a colouring matter or a pigment such as mica, or soot or amineral colour or the like. The impregnated or coated material is,without being dried, optionally in the stretched state, taken throughone of the precipitating baths described in Example I, whereuponthematerial is washed and dried.

Instead of strong hydrochloric acid there may be used in the foregoingexamples a strong nitric acid, for example such as contains 60 to 90 percent. of HNOg, or phosphoric acid, for example of 1,5 to 1,86 specificgravity, (i. e. about 67.5 to 99% H PO or arsenic acid, for example suchas contains from 60 to 90 per cent. of H AsO In the foregoing examples,in the preparation of viscose, instead of wood pulp, there may be usedbleached cotton, or cellulose treated in the cold or in the heat withdilute acids, for example hydrochloric or sulphuric acid, in short anykind of cellulosic bodies employed in, or proposed for the manufactureof viscose.

The expressionstrong hydrochloric acid or hydrochloric acid containingat least 25 per cent. of hydrogen chloride means in the description andclaims hydrochloric acid of 25 per cent. strength and above.

The expression: artificial material in the description and claims isintended to mean: artificial threads and filaments of any kind, forexample artificial silk, staple fibre, artificial cotton, artificialwool, artificial hair, films, plates, coatings and fillings of any kind.v

The expression cellulose is intended to mean cellulose or cellulosehydrate, as the body regenerated from viscose is regarded by somecellulose chemists as cellulose by others as cellulose hydrate.

The expression heating in the claims is intended to cover any known kindofheating, steaming included.

The statements in the description and claims regarding percentagesrelate to percentages by weight.

The present application is a division of my copending application Ser.No. 113,582 filed June 3, 1926.

Having described my invention, I claim:

1. A process which comprises forming viscose into an artificialmaterial, and contacting the same with an acid selected from the hereindescribed group consisting of hydrochloric acid, nitric acid, phosphoricacid and arsenic acid, of a strength suflicient to plasticize theprecipitated cellulose.

2. The process of coagulating a viscose 2 which 'comprises contacting itwith hyclrochloricfacidofat'least about to 4:0 per cent.

strength, I

3. The process of coagulating a viscose which comprises-contacting it'with'a liquid which contains at least about 25 to 40 per cent.

hydrogen chloride.

' 4. The process o lflmanufacturing artificial thread of high drytenacity which comprises contacting a threadlike stream of a viscosewitha liquid which contains at least about 25 to 4:0percent. hydrogenchloride.

5.-The process of manufacturing artificial 7 material which comprisesbringing a viscose into the form o'f an artificial material; acting uponit witha liquid which contains at least about 25 to l0 per cent.hydrochloric acid to coagulate the viscose and washing the coagulatedviscose.

' 6. A-process whichcomprises forming an artificial'materialfrom viscoseand treating said artificial material with hydrochloric 7 acid of aconcentration sutficient to -p-lasticize precipltated cellulose. V 7. A.process which comprises contacting viscose witha phosphoric acid bath ofabout 1.5;to 1.86 specific gravity;

8. Aprocess which comprises shaping viscose into" the shape of anartificlal mater] a1 and contacting same with phosphoric acid of atleast 67.5%str'ength.

viscose'with a nitric'acid 9. A'pro'cesswhich comprises contacting bathof about to strength. i r 10. A process which comprises shaping viscoseinto the shape of an artificial material and contactingfthe same withnitric acid ofat least 60% concentration.

-11. A process which comprises forming viscose into the shape of anartificial material, and subjecting said formed material I to contactwith an acid bath selected from the herein describeolgroup consisting of(a) a bath containing about 25 to 40% of H01 (6) a bath containing about60 to 90% of HNO' (c) a bath containing about 67.5- to 99% of H PO and(01) abath containing about 60 to 90% of H AsO c In testimony whereof IaffiX, my signature.

LEON LILIENFELD. iv

